Scientific evidence still doesn't clearly explain climate change and it's normal to be skeptical, claims former Conservative cabinet minister Maxime Bernier in an open letter published Wednesday.

Not all scientists agree on what causes climate change, and many experts underestimate the role of the sun and other factors, Bernier, who is still an MP, wrote in his op-ed in the Montreal newspaper La Presse.

Canada's Conservative government would be irresponsible to spend billions of dollars to reduce greenhouse gas emissions given the contradictory science available, Bernier said.

The Quebec politician said the views expressed in the letter are his personal opinion but correspond to those of his political party.

Bernier later told The Canadian Press that he simply meant to say it's important to be cautious when it comes to climate change.